Move NativeLib::filename to the rmeta-link archive member by mehdiakiki · Pull Request #156735 · rust-lang/rust

mehdiakiki · 2026-05-19T01:30:27Z

Second PR in #138243
Moves NativeLib::filename out of rmeta into lib.rmeta-link archive member that was introduced in the first PR. Filename is a link time only data so requiring a full metadata decode should be avoided. It is stored as (name, filename) pairs keyed by name, the new MetadataLoader::get_rlib_native_lib_filenames patches it back on decode. Also bumped METADATA_VERSION from version 10 to 11. Added also new round trip test and existing bundled-libs tests still pass.

rustbot · 2026-05-19T01:30:33Z

r? @dingxiangfei2009

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rustbot · 2026-05-19T01:46:13Z

This PR was rebased onto a different main commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

mehdiakiki · 2026-05-19T02:05:27Z

r? @petrochenkov
cc @bjorn3

mehdiakiki · 2026-05-20T01:24:00Z

Started working on it today. Should have it ready soon.

Move NativeLib::filename to the rmeta-link archive member

petrochenkov · 2026-06-03T14:51:46Z

This all needs to be rewritten properly.

We need something similar to CStore but local to link.rs and loading link metadata entries for crates on demand.
And the same thing for native libraries (only filenames atm) as well.

rust-bors · 2026-06-03T15:05:36Z

☀️ Try build successful (CI)
Build commit: 7894972 (7894972d636d0fdd9341b6f4bbaa9ec76818073f, parent: 53509ca37e3b507887607c2f4a7f23bd4838f099)

rust-timer · 2026-06-03T15:46:39Z

Finished benchmarking commit (7894972): comparison URL.

Overall result: ❌ regressions - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.5%, 0.5%]	1
Regressions ❌ (secondary)	0.6%	[0.2%, 1.7%]	12
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.5%	[0.5%, 0.5%]	1

Max RSS (memory usage)

Results (primary 8.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	8.0%	[8.0%, 8.0%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	8.0%	[8.0%, 8.0%]	1

Cycles

Results (secondary 3.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	3.5%	[2.5%, 4.7%]	3
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 509.672s -> 510.294s (0.12%)
Artifact size: 400.72 MiB -> 400.70 MiB (-0.01%)

petrochenkov · 2026-06-03T15:51:51Z

Some regressions on linking-heavy workloads like large-workspace.

mehdiakiki · 2026-06-04T12:05:51Z

read_from_path opens and parses the rlib 2+ times per crate and this happens even for crates that don't have that that bundled native libs. I guess since this regression is happening for regular code we need to fix it right now. Only read for a filename when needed i.e. upstream crate linked statically and contains bundled native libs. This will reduce reads to just one instead of many right now. Is this ok to try now or should I do the loader like you suggested directly in this PR?

petrochenkov · 2026-06-04T12:48:11Z

I won't have time to look until next week.
If you do the cstore analogue, could you do it in a separate PR? It would be useful for the existing rmeta-link already, even without native_lib_filenames.

mehdiakiki · 2026-06-04T12:54:37Z

@petrochenkov sure will do.

rustbot · 2026-06-17T01:01:50Z

⚠️ Warning ⚠️

This PR is based on an upstream commit that is older than 28 days.

It's recommended to update your branch according to the rustc-dev-guide.

mehdiakiki · 2026-06-20T22:46:51Z

@rustbot ready

mehdiakiki · 2026-06-20T22:51:09Z

@petrochenkov I split the cstore out into #158194 once it lands I will rebase this PR on top of it so that the native_lib_filenames reads go through the cache instead of redoing the parsing for each rlib.

petrochenkov · 2026-06-22T14:55:49Z

Blocked on #158194.
@rustbot blocked

…oded lib.rmeta-link archive members, and routes add_archive read through it so each rlib link metadata is decoded at most once per link. This is a demand that originated from the discussion in rust-lang#156735 and we split it out as its own PR. It gives that PR a decode once path tp read instead of reparsing each rlib per crate once native_lib_filenames moves to a link time read.

…=petrochenkov Adds RmetaLinkCache a per-link cache that uses path as the key of dec… Adds `RmetaLinkCache` a per link and path keyed cache of decoded `lib.rmeta-link` archive members and routes the add_archive read through it so that each rlib link metadata is decoded only one per link at most. This is a request that originated from the discussion in rust-lang#156735 and we split it out as its own PR. It gives that PR a decode once path to read instead of reparsing each `rlib` per crate, and this will be in effect once `native_lib_filenames` moves to a link-time read. Part of rust-lang#138243

rustbot assigned dingxiangfei2009 May 19, 2026

rustbot added A-run-make Area: port run-make Makefiles to rmake.rs S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels May 19, 2026

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mehdiakiki force-pushed the fix/rlib-digest branch from 053432f to 8f96681 Compare May 19, 2026 01:46

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mehdiakiki force-pushed the fix/rlib-digest branch from 8f96681 to 5a93c75 Compare May 19, 2026 02:00

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 3, 2026

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rust-bors Bot pushed a commit that referenced this pull request Jun 3, 2026

Auto merge of #156735 - mehdiakiki:fix/rlib-digest, r=<try>

7894972

Move NativeLib::filename to the rmeta-link archive member

petrochenkov added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 3, 2026

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Jun 3, 2026

Move NativeLib::filename to the rmeta-link archive member

b8f2284

mehdiakiki force-pushed the fix/rlib-digest branch from ac119d2 to b8f2284 Compare June 17, 2026 01:01

mehdiakiki mentioned this pull request Jun 20, 2026

Adds RmetaLinkCache a per-link cache that uses path as the key of dec… #158194

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rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jun 20, 2026

rustbot added S-blocked Status: Blocked on something else such as an RFC or other implementation work. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jun 22, 2026

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rust-timer commented Jun 3, 2026

Overall result: ❌ regressions - please read:

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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